package com.example.demo.service;


import com.example.demo.dao.DiscussPostMapper;
import com.example.demo.entity.DiscussPost;
import com.example.demo.util.SensitiveFilter;
import com.github.benmanes.caffeine.cache.CacheLoader;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.LoadingCache;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.util.HtmlUtils;

import javax.annotation.PostConstruct;
import java.util.List;
import java.util.concurrent.TimeUnit;

@Service
public class DiscussPostService {

    private static final Logger logger = LoggerFactory.getLogger(DiscussPostService.class);

    @Autowired
    private DiscussPostMapper discussPostMapper;

    @Autowired
    private SensitiveFilter sensitiveFilter;

    @Value("${caffeine.post.max-size}")
    private int maxSize;

    @Value("${caffeine.post.max-seconds}")
    private int expireSeconds;

    // Caffeine核心接口: Cache, LoadingCache, AsyncLoadingCache

    // 帖子列表缓存
    private LoadingCache<String, List<DiscussPost>> postListCache;

    // 帖子总数缓存
    private LoadingCache<Integer, Integer> postRowCache;

    @PostConstruct
    public void init() {
        // 初始化帖子列表缓存
        postListCache = Caffeine.newBuilder()
                .maximumSize(maxSize)
                .expireAfterWrite(expireSeconds, TimeUnit.SECONDS)
                .build(new CacheLoader<String, List<DiscussPost>>() {
                    @Override
                    public @Nullable List<DiscussPost> load(@NonNull String s) throws Exception {
                        if (s == null || s.length() == 0) {
                            throw new IllegalArgumentException("参数错误！");
                        }

                        String[] params = s.split(":");
                        if (params == null || params.length != 2) {
                            throw new IllegalArgumentException("参数错误！");
                        }
                        int offset = Integer.valueOf(params[0]);
                        int limit = Integer.valueOf(params[1]);

                        // 这里可以加一个二级缓存

                        logger.info("Load post list from DB.");
                        return discussPostMapper.selectDiscussPosts(0, offset, limit, 1);
                    }
                });

        // 初始化帖子总数缓存
        postRowCache = Caffeine.newBuilder()
                .maximumSize(maxSize)
                .expireAfterWrite(expireSeconds, TimeUnit.SECONDS)
                .build(new CacheLoader<Integer, Integer>() {
                    @Override
                    public @Nullable Integer load(@NonNull Integer integer) throws Exception {
                        logger.info("Load post list from DB.");
                        return discussPostMapper.selectDiscussPostRow(integer);
                    }
                });
    }

    public  List<DiscussPost> findDiscussPosts(int userId,int offset,int limit, int orderMode){
        if (userId == 0 && orderMode == 1) {
            return postListCache.get(offset + ":" + limit);
        }

        logger.info("Load post list from DB.");
        return discussPostMapper.selectDiscussPosts(userId,offset,limit, orderMode);
    }

    public int findDiscussPostRows(int userId){
        if (userId == 0) {
            return postRowCache.get(userId);
        }

        logger.info("Load post list from DB.");
        return discussPostMapper.selectDiscussPostRow(userId);
    }

    public int addDiscussPost(DiscussPost post){
        if(post == null){
            throw new IllegalArgumentException("参数不能为空!");
        }

        //转义HTML标记
        post.setTitle(HtmlUtils.htmlEscape(post.getTitle()));
        post.setContent(HtmlUtils.htmlEscape(post.getContent()));
        //过滤敏感词
        post.setTitle(sensitiveFilter.filter(post.getTitle()));
        post.setContent(sensitiveFilter.filter(post.getContent()));

        return discussPostMapper.insertDiscussPost(post);

    }

    public DiscussPost findDiscussById(int id){
        return discussPostMapper.selectDiscussPostById(id);
    }

    public int updateCommentCount(int id, int commentCount){
        return discussPostMapper.updateCommentCount(id,commentCount);
    }

    public int updateType(int id, int type) {
        return discussPostMapper.updateType(id, type);
    }

    public int updateStatus(int id, int status) {
        return discussPostMapper.updateStatus(id, status);
    }

    public int updateScore(int id, double score) {
        return discussPostMapper.updateScore(id, score);
    }
}
